A little stress helps us to adapt. In fact, it can be a great motivator. But long-term stress can upset your health in a lot of ways. Studies have linked chronic stress to many conditions spanning from heart disease, type 2 diabetes, high blood pressure, gastrointestinal problems, depression, fibromyalgia and many more.
Did you know stress is also detrimental to healthy thyroid functions? Before we go into the nitty-gritty of how stress affects your thyroid, let’s get familiar with the workings of the thyroid gland.
How Your Thyroid Gland Works
The thyroid gland, a butterfly-shaped organ, is a part of your endocrine system. It produces thyroid hormones that are involved in regulating several body functions such as metabolism, heat production, brain development, respiration, digestion, reproduction, weight management and so much more.
The thyroid gland makes thyroid hormones; thyroxine (T4) and triiodothyronine (T3), which are released into the bloodstream. Hypothalamus and pituitary are two glands in the brain that work as a team to regulate the levels of thyroid hormones in the body.
Hypothalamus secretes TSH Releasing Hormone (TRH) that cues the pituitary gland to produce thyroid stimulating hormone (TSH)
TSH signals the thyroid gland to make T4 and T3 hormones. More than 90 % of the hormones produced at this stage is in the form of T4, which is relatively inactive.
When the levels of T3 and T4 in the blood rise, the pituitary gland lowers the production of TSH through a negative feedback mechanism.
T4 (inactive prohormone) is converted into the more active T3 in different tissues and organs, such as liver, kidneys and the gut.
T3 enters cells with the help of thyroid hormone receptors present on the cells.
Problems with any of these steps could result in poor production, poor conversion and poor uptake of thyroid hormones by the cells. And as we are going to find out, stress affects these pathways in more ways than one.
Hypothyroidism Versus Hyperthyroidism
One of the most common type of thyroid conditions is hypothyroidism, where your thyroid gland makes less hormones than you need. Most of the body functions that are dependent on thyroid hormones also slow down – resulting in symptoms such as slower heart rate, depression, fatigue, weight gain, dry skin and hair, reduced sweating and constipation. The most common cause of hypothyroidism is Hashimoto’s disease, which is an auto-immune disorder.
On the other hand, hyperthyroidism is where your thyroid gland makes more thyroid hormones than you need. Symptoms include nervousness, rapid heartbeat, hand tremors, fatigue, increased perspiration, infrequent or lighter periods for woman and frequent bowel movement. Your overactive thyroid is mostly caused by Grave’s disease, again an auto-immune disorder. We are soon going to explore the link between stress and auto-immunity.
Let’s first define stress
Stress is not just limited to the negative feelings caused by unreasonable deadlines at work, losing a job, facing a financial problem or separating from your partner. Any change that can negatively alter your body’s natural bio-chemistry and internal balance can trigger stress. By this definition, factors such as blood sugar imbalances, leaky gut, chronic infections, exposure to environmental toxins and of course diet rich in sugar and processed foods can also stress your body. You can say stress comes in many varieties: it can be emotional, mental, physiological and even chemical.
How stress specifically contributes to thyroid disorders?
Your thyroid is extremely sensitive to changes and is negatively impacted by a number of external and internal factors. And among these (that include genetics and autoimmune disorder), chronic stress plays an important role.
- Chronic stress causes HPA dysfunction
Stress disrupts how your Hypothalamus-Pituitary- Adrenal (HPA) axis functions. One of the most important functions that HPA axis controls is: how your body responds to stress.
When you experience stress, your HPA axis releases a series of hormones such as cortisol and adrenaline. This hormonal spurt provides you with a quick burst of energy, makes you less sensitive to pain while increasing your blood sugar levels and heart rate. These bio-chemical changes are meant to gear your body to assess and respond to the stressful situation most efficiently (flight or fight mode). Mind you, this hormonal play is supposed to be short-term. Once the stressor goes away, the body soon returns to its normal state.
What happens when you are facing one stressful situation after another? There is a continuous influx of stress hormones, including cortisol. Your adrenals soon get exhausted, leading to adrenal fatigue. Let’s see how adrenal stress, and increased levels of cortisol, affects your thyroid function:
- Chronic adrenal stress disrupts HPA axis, supressing thyroid gland function. A rise in cortisol levels lowers the production of thyroid hormone. Excess cortisol also impairs the conversion of inactive T4 into active T3.
- T3 hormone needs to be absorbed by the cells to function. This happens with the help of receptors present on almost every cell in the body. But chronic stress (and increased cortisol levels) make these receptors less sensitive to T3, affecting T3 uptake by the cells. It is like having normal T3 levels but due to decreased sensitivity of receptor sites, the cells don’t respond when thyroid hormone comes calling. It is called thyroid resistance, when the cells develop resistance against the thyroid hormone. Studies show that inflammatory proteins released during stress supress thyroid receptor site sensitivity. 
This is the reason why some patients don’t see any improvements in their hypothyroid symptoms even after they take their medication and their blood panel shows normal levels. The fault is not at the ‘production’ stage but at the ‘uptake’ stage due to chronic stress. Increasing your dose won’t help if the cellular receptors don’t respond well.
- Chronic stress overdrives your immune system
Long-term stress, in general, creates an inflammatory environment in the body.  Chronic events of immune and inflammatory responses make the body more susceptible to develop auto-immune conditions of all kinds such as lupus, rheumatoid arthritis, multiple sclerosis, inflammatory bowel disease, asthma, dermatitis and Hashimoto thyroiditis.
Prolonged episodes of chronic stress make your immune system go into an overdrive. An over-reactive immune system keeps launching inflammatory responses and eventually loses its ability to differentiate between healthy and rogue cells. Your body makes anti-bodies that start attacking your own healthy tissues triggering auto-immune disorders such as Hashimoto thyroiditis, where the body creates antibodies that attack its own thyroid tissue.
Cortisol and estrogen relation
Among its many functions, the liver is also responsible for eliminating excess hormones including estrogen from the body. However, continuously elevated cortisol interferes with the liver’s ability to remove superfluous estrogen. Adrenal dysfunction, again caused by chronic stress, can cause the liver to malfunction, reducing its ability to detoxify. In fact, studies show that depression, anxiety and stress levels increase the risk of death by liver disease.
Coming back to estrogen, excess of this hormone:
- Directly affects the ability of your thyroid gland to make hormones
- Stops the liver from converting T4 into T3, the form of thyroid hormone that your cells can actually use for their energy production.
- Increases the levels of thyroid binding globulin or TBG in the body. TBG is one of the transport proteins that binds to the thyroid hormones and carry them in the bloodstream. As long as thyroid hormone remains attached to TBG, it is inactive. Thyroid hormone needs to separate itself from TBG so that it can bind to and activate thyroid receptors present on the cells. This is when cells allow T3 to enter inside. You certainly don’t want to have much of TBG roaming around, high levels of which may slow the entry of T3 into the cells.
- Stress leads to poor gut health
The connection between gut health and thyroid is possibly one of the most crucial yet least understood pieces of the entire story. It is also one of the most overlooked aspects. How is your gut health related to your thyroid health? In many ways, if you believe a study completed in 2011. 
Your gut is home to trillions of bacteria, with a strong influence on your immunity, digestion, metabolism and overall health. This gut flora is a mix of both good and bad, and a healthy balance between their flora population is what is central to your good health. In fact, 80% of your immune system lies within your gut.
Gut dysbiosis, leaky gut and auto-immune connection:
Ongoing stress can deplete good bacteria, creating an imbalance in the gut flora (gut dysbiosis). This imbalance compromises the integrity of the gut lining – producing a plethora of health issues including inflammation and leaky gut.
Your gut lining acts as a protective barrier that allows nutrients to pass through, but keeps a check on toxic substances. But with leaky gut, the tight junctions across the gut lining break apart, forming holes that allow undigested proteins and toxins (and other ‘bad’ stuff) to seep into the bloodstream. Since these substances have no job being in the bloodstream, your body immediately launches an immune attack. Frequent immune responses lead to the formation of antibodies that start destroying the body’s own tissues, including thyroid.
Gut health and T4 to T3 conversion
Your thyroid gland produces both T4 and T3, but it makes more of T4 hormone, which is inactive. T4 is converted into more active T3 in tissues and organs like the gut, liver, kidneys and skeletal muscles. T3 is a form used by the cells.
Nearly 20 percent of this T4 is converted into T3 in the gut. The healthy bacteria in the gut provides a specific enzyme needed for this conversion. Gut dysbiosis, triggered by chronic stress and a lot of other factors, impairs this conversion – leading to T3 deficiency in the blood. It is not surprising why people with poor gut health show symptoms indicative of thyroid disorders.
Gut health and nutrient absorption
Again, poor gut health doesn’t allow the body to absorb the nutrients effectively. Nutrients like iodine, selenium, magnesium, vitamin B12, zinc and vitamin D play an important role in healthy thyroid function.
For example, you need magnesium, zinc and vitamin B12 to make TSH. Minerals like selenium, and Zinc, help in the conversion of T4 into T3. You need vitamin D and vitamin A to help T3 bind with receptors on the cells. If your body is lacking any of these nutrients, many processes in thyroid hormone metabolism take a hit. In fact, a 2015 study showed that low levels of vitamin D are associated with lower TSH levels and increased levels of thyroid autoantibodies – common in people with Graves’ disease and Hashimoto’s disease. 
- Stress elevates blood sugar levels
Chronic stress and resulting cortisol shoot-up also causes your glucose levels to rise steeply. Studies show that “stress can influence the development of type 2 diabetes indirectly by promoting obesity and metabolic syndrome.” 
Sugar imbalances caused by prolonged stress can affect your thyroid too. The connection between diabetes and thyroid disorders is well-established. Poor glucose metabolism can affect the workings of thyroid glands whereas malfunctioning thyroid can cause insulin resistance.  
High sugar levels also contribute to chronic inflammation, a huge risk factor for auto-immune thyroid disorders.
An important take-away here is that conventional treatment for thyroid needs to be integrated with strategies that work to reduce chronic stress. And remember stress can come from any quarter. Over long term, nutritional deficiencies, gut disorders, persistent infections, poor diet, sleep deprivation and emotional distress can put your body under immense stress, disrupting the overall harmony. Addressing these challenges as a whole should be a part of an overall strategy to manage your thyroid disorder.
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- Cohen et al. Chronic stress, glucocorticoid receptor resistance, inflammation, and disease risk. PNAS. 2012.
- Konturek et al. Stress and the gut: pathophysiology, clinical consequences, diagnostic approach and treatment options. J Physiol Pharmacol. 2011
- Arslan et al. Isolated Vitamin D Deficiency Is Not Associated with Nonthyroidal Illness Syndrome, but with Thyroid Autoimmunity. The Scientific World Journal. 2015.
- Marcovecchio et al. The effects of acute and chronic stress on diabetes control. Sci Signal. 2012
- Hage at al. Thyroid Disorders and Diabetes Mellitus. Journal of Thyroid Research. 2011
- Gierach M et al. Insulin resistance and thyroid disorders. Endokrynol Pol. 2014